Combustion head for oil burners and the like



July 4, 1950 w. w. HALLINAN CMBUSTION HEAD FOR OIL BURNERS AND THE LIKE Filed Jan. 21. 1948 s sheets-sheet i July 4, 1950 w. w. HALLiNAN coMBUsTIoN HEAD FOR 011. BURNERS AND THE LIKE Filed Jan. 21, 194s July 4, 1950 w. w. HALLINAN COMBUSTIQN HEAD FOR OIL BURNERS AND 'r1-1E LIKE Filed Jan. 21, 1948 3 Sheets-Sheet 5 76 lIB 6778 '50 NHSB A Mv' Patented July 4, 195.0

OFFICE oo'MBUsTIoN HEAD Fori OIL BURNERs AND THE LIKE Winiam W. Hallman., Racine, Wis. Application January 21, 1948, Serial No. 3,423 '5 claims. (c1. 15s- 76) The present invention relates to combustion heads for oil burners and the like, and is particul'arly concerned with an improved combustion head which is adapted to produce a hollow rotating cylinder of air which becomes a hollow cone of air as it is discharged from the air cone of the combustion head, but which may be so adjusted that the angle of the cone may be varied and the density of the air in the cone may also be varied.

One of the objects of the invention is the provision of an improved combustion head structure in which the air may be adjusted as to its anglek and capacity, and in which the static head of air pressure maintained in the inlet tube may be controlled and the cone of air discharged may be varied as to its density from a full hollow cone to a full solid cone.

Another object of the invention is the provision of an improved combustion head provided with vaned air-inlet ports for producing a rotating cylinder of air, and with other inlet ports for admitting air into the rotating cylinder whereby the density of the air in the cylinder may be adjusted and the amount of air may be adjusted by controlling the size of :said ports, so vthat the characteristics of the air discharge may be adjusted by providing a flame of any size or shape dictated by the construction of the fur- `nace or construction of the fire box.

Another object of the invention is the provizsion of an improved oil burner combustion head -unit, which is adapted to be removed as a unit from the air tube of the oil burner without the :necessity for getting into or disassembling parts -of the furnace.

Another object is the provision of an improved -oil combustion head, which is adjustable in regard to the characteristics of the air discharge 4so that the atomizer may operate in a substantially cool condition at all times, thus eliminating a great deal of service of the burners of the prior art which is necessitated by carbon and oil varnish being driven back into the atomizer and Asolidified by the heat to which the atomizers are -f subjected in the combustion heads of the vprior art.

Another object is the provision of an improved combustion head construction, including a combustion head unit which is self-centeringv and i self-locating at its forward end and which is substantially heat insulated from the llame and .re' and heat of the refractory, by' the use of an insulated locating cone in the air tube.

Another object is the provision of a complete r 'icig', such as cleaning and adjusting the electrodes,

and spark gap in relation to the atomizer and air cone, cleaning and adjusting th-e atomizer to be located in correct relation with respect to the air cone, and making the desired adjustments in the air-inlet ports by means of which the static air head is maintained and aconical airV discharge is obtained which is suited in its characteristics to the size of the nozzle and the shape and characteristics of the fire box. l

Another object is the provision of an improved means for controlling the air inlet ports of a combustion head, by means of which the volume of air and characteristics and shape of the conically discharged air may be controlled, if desired, after the combustion head has been `installed and while it is operating so that these adjustments can be made while the flame is being observed through a suitable sight glass.

Still another object is the provision of an improved combustion head structure, which can be removed as a unit from the air tube by merely disconnecting the ignition leads and the fuel supply tube, and disconnecting a securing device which is located at the rear end of the unit in the air tube where it is conveniently accessible Without disturbing any of the other parts of the furnace except to open the air tube.

Other-objects of the invention will be apparent from the following description and the accompanyingdrawings, in which similar characters of reference indicate similar parts throughout the several views. f

Referring to the three sheets of drawings accompanying the specification,

Fig. 1 is a fragmentary sectional view taken on a horizontal plane passing through the furnace re box, air tube and blower housing on a' plane determined by the axis of the fuel supply tube;

Fig. 2 is a fragmentary sectional View on the larger scale, taken on the plane rof theI line 2-2 of Fig. l looking in the direction of the arrows and showing the construction of the combustion head;

Fig. 3 is a fragmentary transverse elevational view showing the discharge end of the combustion head as it appears from the insideof the fire box, on a plane determined by thev lines 3-3 of Fig. 2 looking in the direction of the arrows;

Fig. 4 is afragmentary' sectional View taken on the plane of the line ll-ll of Fig. 2 showing the turbulator vanes which direct the flow of air into a hollow rotating cylinder of air;

Fig', 5 is a fragmentary sectional View taken on the plane of the line 5 5 of Fig. 2, looking i'n the direction ofthe arrows, and showing the air inlet ports which supply air to the inside of the rotating cylinder of air and Figlf isa fragmentary elevational view taken on the' plane of the line (i4-( of Fig. 2, looking in aperture I4 for receiving the air tube I5, which leads to a blower housing I6 havin-g an inlet I1` at one of its ends.

The blower housing I6 may be substantially cylindrical and provided with a closure cover I8, I9 at each end, the cover I9 being provided with the centrally located air inlet I 1 formed by an in-I wardly tapered part 20 of the cover I9. Air inlet I1 has a transverse frame member or bridge 2l with a threaded bore for receiving the threaded endof a screw bolt 22, lwhich bolt carries a circular cover 23. The cover 23 maybe adjusted to positions close to or farther away from the air inlet opening I1 to meter the amount of air passing into vthe blower housing I5, so that sufficient air may be supplied for combustion, depending upon the size of the nozzle. `The blower may consist of a centrifugal air impeller 24 carried by the shaft 25 of the motor 2B, and the other end of the shaft 25 may drive a' fuel pump unit 21, the fuel pump unit including the usual strainer, gear pump and pressure regulator valve. Conduit 28 extends from the outlet of the fuel supply unit 21 to a detachable fitting 25 on the fuelsupply tube or pipe 3D of the combustion head unit, which is indicated by the numeral 3l.

rIhe air tube I is provided, adjacent its forward end, with an outward annular attachment flange 32 adapted to be attached to the furnace shell I I by a plurality of screw bolts 33 threaded into threaded bores in the shell AI I. Attachment flange 32 is located rearwardly of the inner end 34 of the air tube I5 suiciently so that the end of the'air Atube 34 is flush' with the inner wall of the fire box I3 when the attaching flange 32 is secured to the furnace shell I I. In order to protect the combustion head against flame and heat `from the refractory 'and to support the combustion head at its forward end, the air tube I5 supports `a frusto-conical steel collar'35 at its discharge end, the largest end 35 of the frusto-coni'cal collar 35 engaging the inside of the air tube I5 and being welded 4to the air tube so that the small end of the frustoconical collar 35 is flush with the end34 of the lair tube. Thesmall end of this frusto-conical collar'35 may be provided with an outwardly turned anfnular flange 31 serving as an anchoring forma'- tion for securing the cementitious filling of heat insulation 38, which is located outside of the frus'- to-conical collar 35 and inside the end of the air tube, and is finished with an outer surface 39 flush with the inside of the fire box I3 at its side corners 4D.

The rigid insulation 38 is adapted to protect the combustion head unit 3I from the heat of the llame and the heat radiated from the refractory lining I2-, and aids materially in keeping the atomizing nozzle cooler so that carbon and oil varnish from the fuel is not accumulated in the atomizer and hardenedr by heat, as it is in the prior art devices. This greatly reduces the service necessary on the oil burner.

` The frusto-conical collar 35 has a frusto-con-` ical inner surface 4I which tapers toward the discharge end, and is adapted to receive and support the tapered forward extension 42 on the turbulator 43 of the combustion head 3l. The forward extension 42 of the turbulator 43 may comprise: a steelforfiron casting, which is provided with a frustofconical wallf44, having at its rear end a radially extending attaching flange 45 provided with a plurality of apertures 46 for receiving screw bolts 41.

The screw bolts are threaded into threaded bores-48 in the end flange 49 of the turbulator, whereby the forward extension 42 supports the turbulator 43. An asbestos gasket 50, provided i with apertures for the screw bolts 41, is preferably interposed between the flanges 45 and 49, thus aiding in insulating the turbulator housing from the cone 42 and also aiding in securing an air-tight fit. The only heat conduction between cone 42 and turbulator 43 is through bolts 41.

At its forward end the cone 42 has an inwardly curved partially spherical flange 5I terminating in an inwardly extending lip 52, which forms a circular discharge aperture 53. The inner sur' face `54 of the lcurved flange 5I may be substantially frusto-conical, and the outer surface `55 may be partially spherical kand is preferably ground to shape.

The partially spherical surface 55 'engages in the conical opening 56 at the restricted end of the collar 35, but is larger than the opening 56 so that spherical surface 55 may be seated in the cone 35. The surface 55, being a surface of revolutiommay be seated in the end of the cone 35 at any of ay multiplicity of different angles as it forms a substantially universal seat, which is substantially air tight and which automatically centers the end of the cone 42 in the air tube No other support is required for the discharge end of the combustion head' unit 3|, the cone 42 being held in the conical collar 35 by means of a securement at the other end of the combustion head unitA 3|.

The turbulator 43 may consist of an aluminum casting of substantially cylindrical shape overall, consisting of a larger body portion 51 and a smaller cylindrical extension 58. The body portion 51 includes a plurality of annular flanges like the end flange 49, `which. may be indicated at. 59, 6G and 5I. The external surfaces 62 of all of these flanges may be substantially cylindrical, and'may be ground to nt the inner surface of a metal band 63 so that metal band 63 may be used to cover or uncover varying amounts of the inlet ports 64, depending upon the axial adjustment of the band 63.

The band` 63 may consist "of a strip of sheet steel bent to cylindrical shape, and having a substantially air-tight .fity about thesurfaces 52 on the turbulator 43. The band B3 may have a pair of radially extending Ysecuring flanges 55, 66 provided with apertures for lreceiving the screw bolt 61 having a nut 68. By means of the screw bolt 61 and nut 6.8 the metalv band 6.3 may be flxedly secured at any`axiall'y adjusted position on the turbulator 43,y being held in that position by friction. y

The turbulatorflanges14959, Eiland 6I are joined by curved vanes 69 v (Figure 4), which are an integral part of the turbulator'43 and extend from the outer surface 62 of the Yflanges '49, 59-6I to the inner surface 1 0 of these flanges. The vanes 69 may be referred to herein as,4 tangential vanes or spiral vanes, by which terms I mean that they are curved and extend peripherally so that theyl direct the air corningfrom.

the ports 64 in concentric rotary jetsclose to the outer wall of turbulator 43. Thus the air emerges from the vanes to form a hollow rotating cylinder of air in the turbulator 43 and cone 42. As this hollow cylinder of air progresses forwardly through the cone 42 and out of its discharge aperture 43 it is shaped into a rotating conical discharge of air and combustion gases.

The metal band 63 may be made wide enough to cover any desired amount of the turbulator ports 64, but as a certain amount of rotating air is required, in any event, it is only necessary to cover those ports which are intended to be controlled or regulated. Thus the band 63 is illustrated as extending from the flange 6| to flange 59, leaving the ports between flanges 49 and 59 always uncovered.

The ports between flanges 49 and 59 are made wider than those between the other flanges 59- 6|, because the size of ports between flanges 49 and 59 is sufficient to provide air for a predetermined size of nozzle. For example, the always open ports 64 between flanges 49 and 59 may be sufficient for a one-gallon nozzle, while the additional port area between flanges 59 and 69 may provide additional air for a two-gallon nozzle. Thus the rotating cylinder of air may be adjusted as to its volume for nozzles of different size by moving the metal band 63 axially.

The end flange 6| of the turbulator 43 supports the smaller cylindrical extension 58, which has an outer cylindrical wall surface 1| to be engaged b-y metal band 12. The cylindrical extension 58 has radially extending ports 13 between the axially extending struts 14, which struts carry the closed end wall 15. The metal band 12 in this case is wide enough to cover the ports 13, and it is again provided with radial securing flanges 16, 11 and a through bolt 18 with a nut 19 for clamping the band 12 in any desired axial position.

In this case it will be noted that the ports' 13 are merely radial ports without vanes to direct the air in a rotating motion, and the air coming in at the ports 13 of the extension 58 is directed to the interior of the rotating cylinder of air that is produced by the main body 51 of turbulator 43.

By regulating the amount of air passing in at the ports 13 (Figure 5) to the interior of the rotating cylinder of air, the density of the air at the discharge end 53 may be varied from a hollow cone to a fully solid cone, and this includes intermediate densities in which the discharged cone of air has a rotating wall of different thicknesses.

Furthermore, I find that the angularity of the cone of air discharged from the opening 53 may be varied by regulating the amount of air passing in at the ports 13 to the central portion of the head. The angularity of the conical discharge from the opening 53 may be varied from .approximately a cone angle vof 100 degrees to 20 degrees, while at the same time the cone may bc made a solid air cone or a hollow air cone by also regulating the air controlled by the band 83. It will be noted that the extension 58 of the turbulator 43 is smaller than the main body 51, as shown in Figure 5, so that the iianges 16 and 11 on the smaller band 12 may be received within the larger band 63. This permits the larger band to be adjusted toward the right, overlappingthe extension 58 and its band 12. f

The rear wall 15 of the turbulator 43 ispref erably provided with an integral central lug 88, having a centrally located bore 8|, which is concentric with respect to the turbulator and adapted to receive the fuel tube 38. The fuel tube 30 carries an atomizing nozzle 82 in the cone 42, and the position of the nozzle in the combustion head maybe adjusted by moving the combustion head longitudinally of the fuel supply tube 30.

The combustion headis clampedl in proper adjusted position by a set screw v|05 threaded into a threaded bore 83 communicating With the central bore 8|, so that the set screw may engage the fuel supply tube 30. The lug preferably has a substantial axial length, so as to give an elongated bearing surface for its bore 8| on the fuel supplytube 30 to hold the combustion head substantially concentric with the fuel tube over the full length of the combustion head.

Thus the atomizer nozzle 82 will be located centrally of the cone 42, and is held by having a lbore 8|v of substantial length and centrally located. The lug 80 is preferably widened at one side, as shown in Figure 6, forming clamping members 84, 85 and 86, separated by asaw cut slot 81. This enlargement of the lug 80 has a pair of axially extending bores 88, 89, of sufficient size to receive the two porcelain sleeves or insulators 90, 9|, which carry the high tension conductors that terminate in electrodes 92, 93.

These electrodes have inwardlyl turned end portions which are .pointed andare accurately' spaced to form the air gap-94, preferably located above the nozzle end and substantially flush with the end of the nozzle so that the ignition elec-1 trodes may be located out of the flame, but close enough to ignite the fuel discharged from the nozzle.

The connectors carried by the rear end of the electrodes 92, 93 are connected by suitable ,detachable conductors 96 to the high voltage side of van ignition transformer, which is suitably controlled to provide ignition voltage when-ever it is required.

The fuel supply tube 39 is supported at its rear end(Figure 2) by transversely extending frame members 91 provided with clamping means 98, and secured to the inside of the air tube I5 so that the fuel supply tube may be iixedly and centrally secured by means of the frame member 91 at the rear end of the air tube l5. This rear end securement is only made after the cone 42 is pushed into a tight seatl in the collar 35 o'f air tube |5,and thus the securement at the rear end is allthat is necessary to center the combustion head automatically and hold it in adjusted position.

. The combustion head comprising the turbulator, cone, nozzle, electrodes and the air adjustment bands may be removed with the fuel supply tube as a unit without disturbing the furnace, exceptto open the air tube I5. It is only necesn sary to disconnect the A.high tension leads 98 and the fuel supply connection at 29, whereupon the clamping means at 98 may be released and the combustion head removed.

Thus the electrodes may be checked as to air gap and as to proper location with respect to the nozzle and the cone. The central location of the nozzle in the cone and its axial position may be checked and rectified by bending the fuel supply tube slightly or by-moving the turbulator axially on the fuel supply tube and securing it with the set screw |05.

The rotating air supply may be adjusted by adjusting the band 163 axially; and the internal or central air supply may be adjusted by adjusting the axial position `of the band 12; and the shape and size of the conical air discharge, as well as its density, may be controlled by adjusting these air control bands.

The air tube I5 preferably has a metal dam 99 welded across the lower inner surface just behind the turbulator, and has a channeled member (Fig. 3) welded to the lower inside wall and ypassing through the rigid insulation 38 and through an aperture lill (Fig. 2) in the rear end of cone 42. f

The air tube I is also preferably pointed slightly downward toward its front end so that any leakage of oil from nozzle 82 will drain into the fire pot through the opening provided by the vchannel 100;- 1

It has already Ibeen `pointed out that the combustion head is automatically centered and seated-by 'having its -forward end shoved into tight contact with the inside of the conical collar carried by the air tube.

When the rearfend of the combustion head is secured by securing the fuel supply tube to the rear end Yof the Aair tube, the combustion head installation is completed. Thus the combustion head is -oonvenientlyvremovable rv'as a unit and may be adjuStedandserViCed, outside the burner.

In some embodiments-of 4the invention they air bands -63 and 12 vmay be Ysldably mounted and `carried by rods mounted in guides on the air tube, and provided with actuating means so that the bands can be slid axially fromjthe outside of the burner. Thus an adjustment of the-air can be made vwhile the flame Yis being observed through the fire door.

The operation of the burner is as follows: As the fuel is supplied through the fuel supply tube 36 from the pump, under suitable pressure and volume for the nozzle 82, it is atomized bythe nozzle and sprayed in a rconical form-out ofthe combustion head discharge aperture-53. The air supplied under suitable pressure by fthe blower passes down the airtube l5 and in at thefports 64 in the turbulator 43, where the vanes y69 4cause the air toyrotaterinside the turbulatoryforrning azh'ol'lovvrotating'icylinder Vof air; and as it passes through aperture 53 kit takes the form of a hollow cone, which Vwil-l form Ja hollow saucer-shaped flame of approximately 100 degrees.

If additional airis suppliedto the interior of this cylinder Vof air through the ports 13 in the turbulator extension $8, and :by means of the adjustment of the band 1-2 the angularity of the conical air discharge maybe variedfrom approximately 100 degrees cone to 20 'deg-rees. This determines the shape ofthe flameor 'combustion area and enables vthe same combustion head to be used for furnace ilre boxes of different size and shape; and if the band J1-2 is'adjust'ed to fully uncover ports '13, the'flame lshape or angle will be approximately degrees.

The same combustion head may also be used with nozzles of different capacity and sprayrangle; and the density ofthe air inthe conical air discharge may be varied from Aahollow cone to a fully solid cone bythe adjustment of band 12. Thus the present combustion head may be -adjusted 'to take care of many different furnace conditions,and more perfect combustion may be assured under a1l conditions.

By the combination adjustment of the band 63 over ports 64 and that of 'the-*band 112 over ports 7'3, and 4thexair inletplate 23A-over opening 61, 'any combination of air rotation and density under any head pressure'within Vthe capacity range of the blower, can be obtained, Therefore, not only-can the flame be controlled to t any shape combustion chamber and furnace, but also many types of atomizing nozzles having different `spray angles and densities can also be used; and in each instance pulsations and furnace back pressure can ibe overcome, and the bur-ner can be made to work equally as well in one furnacel or boiler as in another, regardless of ytheir design.

My--improved apparatus utilizes an improved method of predetermining the shape and characteristics of the flame discharged from the combustion head ley-introducing air peripherally of the combustion head, and `causing it to rotate to form a hollow cylinder of air, passing this air out of a restricted conical discharge opening, `and at the samel time supplying a predetermined amount of air to the inside of the lhollow cylinder of air to determine and change, at will, the angularity of the conical discharge, as well as the density ofthe air in the conical discharge.

The volume of air discharged may also be regulated by means of my apparatus, which is also so insulated and cooled that it operates in a much cooler condition than the devices of the prior art, whereby the nozzle is not clogged with carbon or oil varnish, which is baked to a hard condition, due t0 the heat in the devices of the prior art. Thus less nozzle servicing is necessary when the present apparatus isemployed.

While I have illustrated -a preferred embodiment ofmy invention, many modifications may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details vof construction set forth, but desire to avail myself of all changes within the scope of the appended-claims.

Having thus described my invention, what I claim as new and desire to secure Aby Letters Patent of the United States, is:

` 1. In a combustionhead assembly for oil burners of the nozzle type, the combination of a substantially cylindrical metal air tube open at its rear end and provided at its forward end with a frusto-conical metal collar engaging the inside of the air tube at the larger end of said collar, and being iiush with the end of said air tube at the smaller end of said collar, the space between said collar and said air tube being substantially filled with refractory, asupporting bracket carried by the open end of said air tube and having means for clamping a fuel pipe centrally located on saidbracket in said'tube, and a combustion head unit, said combustion head unit including a supporting fuel pipe, a nozzle carried by the end ofsaid fuel pipe,'a combustion head carried by' the fuel pipe and comprising a metal member having ajrear wall'facing toward the open end of said fuel pipe, said rear Wall having a hub enlargement surrounding an axial bore extending through the rear wall, for receiving said fuel pipe, said hub being provided with clamping means for clamping said combustion head in predetermined axial position on said fuel pipe, said rear Wall also having a `pair of eccentric through bores for receiving insulated ignition electrodes, .and clamping means for clamping said electrodes, a pair of'ignition electrodes provided at theirrear ends with elongated refractory insulating tubes arranged insaid latter bores, said electrodes having their ignition ends disposed laterally lof but adjacent Athe discharge end of said nozzle. said combustion head being of a size smaller than said air tube, and having a generally cylindrical body provided with a multiplicity of peripherally open air ports forv receiving air fromy said tube, the said combustion head being provided on its forward end with a frusto-conical metal restricting member open at both ends and communicating at its rear with the said cylindrical body, said restricting member being provided at its discharge end with an inwardly extending peripheral flange which has a frusto-conical surface on its inner side for determining the frusta-conical shape of the combustion flame discharged from said combustion head, and provided on its outside with a partially spherical annular surface, said partially spherical annular surface being of a larger diameter than the smaller end of said first-mentioned metal collar, theengagement of spherical surface portions inside a conical discharge opening in the air tube effecting an air-tight seal around the inner end of the combustion head, while permitting a substantially universal adjustment or movement of the outer end of the fuel pipe without detracting from the tightness of said air seal, the first-mentioned metal collar guiding the combustion head into air sealing relation and into centered position as the combustion head is moved into said collar, where it can be secured solely by the clamping means engaging the rear end of the fuel pipe.

2. In a combustion head assembly for oil burners of the nozzle type, the combination of a substantially cylindrical metal air tube, open at its rear end and provided at its forward end with a frusto-conical metal collar engaging the inside of the air tube at the larger end of said collar, and being flush with the end of said air tube at the smaller end of said collar, the space between said collar and said air tube being sub-` stantially filled with refractory, a supporting bracket carried by the open end of said air tube, and having means for clamping a fuel pipe centrally located on said bracket in said tube, and a combustion head unit, said combustion head unit including a supporting fuel pipe, a nozzle carried by the end of said fuel pipe, a combustion head carried by the fuel pipe and comprising a metal member having a rear wall facing toward the open end of said fuel pipe, said rear wall having a hub enlargement surrounding an axial bore extending through the rear Wall, for receiving said fuel pipe, said hub being provided with clamping means for clamping said combustion head in predetermined axial position on said fuel pipe, said rear wall also having a pair of eccentric through bores for receiving insulated ignition electrodes, and clamping `means for clamping said electrodes, a pair of ignition electrodes provided at their rear ends with elongated refractory insulating tubes arranged in said latter bores, said electrodes having their ignition ends disposed laterally of but adjacent the discharge end of Said nozzle, said combustion head being of a size smaller than said air tube, and having a generally cylindrical body provided with a multiplicity of peripherally open air ports for receiving air from said tube, the said combustion head being provided onits forward end with a yfrusto-conical metal restricting member open at,v bothl ends Aand communicating at its rear with thesaid cylindrical body, said restricting member being provided at its discharge end with an inwardly extending peripheral flange which has a Truste-conical surface on its inner side for determining the frusto-conical shape of the combustion flame discharged from said combustion i head, and provided on its outside with a partially spherical annular surface, said partially spherical .annular surface being of a larger diameter than the smaller end of said first-mentioned metal collar, the engagement of spherical surface p'or-l tions inside. a conical discharge opening in the air tube effecting an air-tight seal around the inner end of the combustion head, while permitting a substantially universal adjustment' 6r movement of the outer end of the fuel pipe with'- out detracting from the tightness of said air seal, the first-mentioned metal collar guiding the combustion head into air sealing relation and into centered position as the combustion head is vmoved into said collar, where it can Vbe secured solely by the clamping means engaging the rear' end of the fuel pipe, the said air tube being provided on its outside, adjacent its `discharge end, butA spaced sufficiently from the discharge end to bring" the discharge end into a position flush with the inside of a furnace Wall, with an annularr attaching flange welded to said metal tube, and having apertures for reception of securing members by means of which it may be secured to the metal shell of a furnace, the said attaching flange being shaped for air-tight engagement with the side wall of the shell of the furnace'.

3. In a combustion head assembly for oil burners of the nozzle type, the combination of a' substantiallycylindrical metal air tube open at its rear end and provided at its forward end with a frusto-conical metal collar engaging the inside of the air tube at the larger end of said collar, and being flush with the end of said air tube at the smaller end of said collar, the space between said collar and said air tube being substantially filled with refractory, a supporting bracket carried by the open end of said air tube and having means for clamping a fuel pipe centrally located on said bracket in said tube, and a combustion head unit, said combustion head unit including a supporting fuel pipe, a nozzle carried by the end of said fuel pipe, a combustion head carried by the fuel pipe and comprising a metal member having a rear wall facing toward the open end of said fuel pipe, said rear wall having a, hub enlargement surrounding an axial bore extending through the rear wall, for receiving said fuel pipe, said hub being provided with clamping means for clamping said combustion head in predetermined axial position on said fuel pipe, said rear wall also having a pair of eccentric through bores for receiving insulated ignition electrodes, and clamping means for clamping said electrodes, a pair of ignition electrodes provided at their rear' ends with elongated refractory insulating tubes arranged .in saidlatter bores, said electrodes having their ignition ends disposed laterally of but adjacent the discharge end of said nozzle, said combustion head being of a size smaller than said airtube, and having a generally cylindrical body' providedl with a multiplicity of peripherally open air ports for receiving air from said tube, the said :combustion head being provided on its'forward end with a yfrusto-conical metal restricting member open at both ends and communicating at` its rear with the said cylindrical body, said restricting member being provided at its discharge end with an inwardly extending peripheral flange which has a frusta-conical surface on its inner side for determining the frusto-conical shape of the combustion flame discharged from said combustion head, and provided on its outside with a partially spherical annular surface, said 'partially spherical annular surface being of a Alarger diameter than the smaller end of said firstmentioned metal collar, the engagement of spher- 'ical surface portions inside a conical discharge opening in the air tube effecting an air-tight 'seal around the inner end of the combustion head, while permitting a substantially universal adjustment or movement of the outer end of the fuel pipe without detracting from the tightness' of said air seal, the rst-mentioned metal collar guiding the combustion head into air sealing relation and into centered position as the combustion head is moved into said collar, where it can be secured solely by the clamping means engaging the rear end of the fuel pipe, the said frustoconicalcollar and refractory being provided, ad-` jacent the lower inside of the air tube, with a through conduit for draining liquid fuel from the air tube into the fire pot used with said combustion head, in the event of leakage of liquid fuel from said nozzle.

4. In a combustion head assembly for oil burners of the nozzle type, the combination of a cylindrical metal air tube which is open at its rear end and provided at its discharge end with an axial circular opening of smaller size than the said tube, with a combustion head having a forward extension, said forward extension having a round dischargeV opening bordered by an inwardly extending annular flange which is provided with aninner frusto-conical surface, defining the conicalY shape of the discharge from said combustion head, the said combustion head including a substantially cylindrical metal body closed at its rear end and communicating with said extension at its front end, said body having a fuel pipe located centrally of said air tube and extending through saidrear end and provided with a nozzle located inwardly and centrally with respect to saidvfrusto-conical surface, the said cylindrical body being formed with a forward portion of larger diameter and a rearward portion of smaller diameter, the said smaller cylindrical portion comprising a plurality of externally cylindrical, axially extending struts secured to said rear wall and to an annular end wall of said larger` cylindrical portion, said struts being spaced peripherally from each other to provide yradially extending air ports, and a cylindrical band adjustably mounted for axial adjustment on said smaller cylindrical portion, to adjust the size of said latter air ports, the said larger cylindrical portion comprising a plurality of radially extend-` ing annular flanges spaced axially from each other for guiding the air from said tube into said combustion head in a direction transverse to the axis of said tube, the said annular flanges being joined by a multiplicity of spirally extending vanes, each spirally extending vane extending from the outside of said annular flanges spirally in the same peripheral direction and inwardly to a point adjacent the inside of said annular flanges, and each succeeding spiral vane having its outer portion overlapping the inner end of the next adjacent spiral vane so that the spiral vanes and annular flanges define peripheral ports of rectangularshape whose inlet openings and outlet openings are so directed that the air entering is directedin such manner as to form a whirling air cylinder inside the combustion head, the said annular flanges being adjustably covered 12A by a cylindrical metal band which is adjustable in an axial direction to regulate rthe amount of air supplied to the combustion head from the air tube in a whirling sense, the radial ports in the smaller cylindrical portion of said body supplying air for the inside of said whirling cylinder of air, and the adjustment of all of said ports serving to determine the size and shape of the flame discharged from said combustion head, to adapt the combustion head to re boxes of dilerent sizes and shapes without the necessity for the flame discharged to hit the back wall of the combustion chamber. f

5. In a combustionhead assembly for oil burner of the nozzle type, the combination of a cylindrical metal air tube which is open at its rear end and provided at its discharge end with an axial circular opening of smaller size than the said tube, with a combustion head having a forward extension, said forward extension having a round discharge opening bordered by an inwardly extending annular Ilange which is provided with an inner frusto-conical surface, dening the conical shape of the discharge from said combustion head, the said combustion head including a substantially cylindrical metal body closed at its rear end and communicating with said extension at its front end, said body having a fuel pipe located centrally of said air tube and eX- tending through said rear end and provided with a nozzle located inwardly and centrally with respect to said frustoonical surface, the said combustion head comprising a plurality of radially extending annular flanges spaced axially from each other for guiding the air from said tube into said combustion head in a direction transverse to the axis of said tube, the said annular anges being joined by a multiplicity of spirally extending varies, each spirallyextending vane extending from the outside of said annular flanges spirally in the same peripheral direction and inwardly to a point adjacent the inside of said annular flanges, and each succeeding spiral Vane having its outer portion overlapping the inner end of the next adjacent spiral vane so that the spiral vanes and annular anges dene peripheral ports of rectangular shape whose inlet openings and outlet openings are so directedthat the air entering is directed in such manner as to form a whirling air cylinder inside the combustion head, the said annular flanges and spiral vanes causing the air which passes into the combustion head at its periphery to form awhirling cylinder of air, the size and shape of which may be adjusted by covering predetermined of said ports to form a spreading flame which may be adjusted for furnaces of different characteristics, without the necessity for the llame to engage the back wall of a combustion chamber.

WILLIAM W. HALLINAN.

REFERENCES CITED The following references are of record in the le of -this patent:

UNITED STATES PATENTS Number Name Date 2,222,031 Hammer Nov. 19, 1940 2,262,525 DeLancey Nov. 1l, 1941 2,338,846 l-Iallinan Jan. 11, 1944 2,395,276 Jordan Feb. 19, 1946 

